Low-energy-consumption temperature swing system for CO2 capture by combining passive radiative cooling and solar heating

Temperature-swing adsorption (TSA) is an effective technique for CO2 capture, but the temperature swing procedure is energy-intensive. Herein, we report a low-energy-consumption system by combining passive radiative cooling and solar heating for the uptake of CO2 on commercial activated carbons (CACs). During adsorption, the adsorbents are coated with a layer of hierarchically porous poly(vinylidene fluoride-co-hexafluoropropene) [P(VdF-HFP)HP], which cools the adsorbents to a low temperature under sunlight through radiative cooling. For desorption, CACs with broad absorption of the solar spectrum are exposed to light irradiation for heating. The heating and cooling processes are completely driven by solar energy. Adsorption tests under mimicked sunlight using the CACs show that the performance of this system is comparable to that of the traditional ones. Furthermore, under real sunlight irradiation, the adsorption capacity of the CACs can be well maintained after multiple cycles. The present work may inspire the development of new temperature swing procedures with little energy consumption.